Will Inflation be confirmed by discovering cosmological gravitational waves?

Steven Weinberg forecasts the future

• 18 November 2006

The most important development in physics that I can imagine in the next 50 years would be the discovery of a final theory that dictates all properties of particles and fields. That may be too much to hope for. A major step in this direction would be the discovery of particles like gauginos or squarks that are required by supersymmetry. Alas, we don't know what the masses of these particles would be, and they may be beyond the reach of any particle accelerator.

On the other hand, we can confidently predict breakthroughs in cosmology. We will know whether the density of dark energy varies with time at a rate comparable to the cosmic expansion rate, or is essentially constant - a crucial clue to the nature of dark energy. We will either have confirmed the general idea of inflation by discovering signs of cosmological gravitational waves (which I expect), or we will have ruled out inflation by showing that these gravitational waves are weaker than predicted. We may be using laser interferometers in space to detect cosmological gravitational waves that bear clues about the behaviour of the matter of the universe at energies higher than we can reach in accelerators. But the origin of the universe will remain obscure until we make more progress toward a final theory.

Nothing truly revolutionary is ever predicted because that is what makes it revolutionary.

John D. Barrow forecasts the future

• 18 November 2006

Cosmologists have much to look forward to: the direct detection of dark matter and gravitational waves, the extraction of more secrets of the early universe, the discovery of the cosmic neutrino background, possibly an exploding black hole, understanding dark energy, decisive evidence for or against the existence of other dimensions of space, new forces of nature and the possibility of time travel; perhaps even nano-sized space probes. I could go on.

All this is exciting, but take a moment to think back 50 years and look forwards. None of the greatest discoveries in the astronomical sciences were foreseen. The transformation in the practice of science brought about by the web is barely 30 years old. No one predicted it. Pulsars, quasars, gamma-ray bursts, the standard model of particle physics, the isotropy of the microwave background, strings and dark energy were equally unexpected. None of these was predicted 50 years ago.

Perhaps scientists are as blinkered as the politicians and economists who failed to foresee the fall of the Iron Curtain and the climatic implications of industrialisation. Yet this myopia may not be a fault. Perhaps it is a touchstone. If you can foresee what is going to happen in your field over the next 50 years then maybe it is mined out, or lacking what it takes to attract the brightest minds. Nothing truly revolutionary is ever predicted because that is what makes it revolutionary.

We may sequence an individual's genome for $1000 and live to 100

Francis Collins forecasts the future

• 18 November 2006

Fifty years from now, if I avoid crashing my motorcycle in the interim, I will be 106. If the advances that I envision from the genome revolution are achieved in that time span, millions of my comrades in the baby boom generation will have joined Generation C to become healthy centenarians enjoying active lives.

How do we get from here to there? For starters, we must develop technologies that can sequence an individual's genome for $1000 or less. This will enable healthcare providers to identify the dozens of glitches that we each have in our DNA that predispose us to certain diseases. In addition, we need to unravel the complex interactions among genetic and environmental risk factors, and to determine what interventions can reduce those risks. With such information in hand, new treatments will be developed, and our "one-size-fits-all" approach to healthcare will give way to more powerful, individualised strategies for predicting and treating diseases - and, eventually, preventing them.

The challenge doesn't stop there. We are already setting our sights on the ultimate nemesis of Generation C: ageing. Genomic research will prove key to discovering how to reprogram the mechanisms that control the balance between the cell growth that causes cancer and the cell death that leads to ageing. It is possible that a half-century from now, the most urgent question facing our society will not be "How long can humans live?" but "How long do we want to live?"

Parallel universes may be discovered in 50 years

Max Tegmark forecasts the future

• 18 November 2006

In 2056, I think you'll be able to buy a T-shirt on which are printed equations describing the unified physical laws of our universe. All the laws we have discovered so far will be derivable from these equations.

We will have confirmed beyond doubt, through observation, that what we now call the big bang wasn't the beginning of everything, merely the time when our part of space stopped undergoing an explosive stretching called inflation. We will have understood the physics of inflation well enough to know that inflation continues forever in some faraway places, and that in other places where it has ended and allowed life to evolve, the T-shirts on sale mostly have different equations.

The existence of such "parallel universes" will be no more controversial than the existence of other galaxies - then called "island universes" - was 100 years ago. This idea was controversial until Edwin Hubble settled it in 1925.

We will understand the moment of the big bang

Sean Carroll forecasts the future

• 18 November 2006

The most significant breakthrough in cosmology in the next 50 years will be that we finally understand the big bang.

In recent years, the big bang model - the idea that our universe has expanded and cooled over billions of years from an initially hot, dense state - has been confirmed and elaborated in spectacular detail. But the big bang itself, the moment of purportedly infinite temperature and density at the very beginning, remains a mystery. On the basis of observational data, we can say with confidence what the universe was doing 1 second later, but our best theories all break down at the actual moment of the bang.

There is good reason to hope that this will change. The inflationary universe scenario takes us back to a tiny fraction of a second after the bang. To go back further we need to understand quantum gravity, and ideas from string theory are giving us hope that this goal is obtainable. New ways of collecting data about dark matter, dark energy and primordial perturbations allow us to test models of the earliest times. The decades to come might very well be when the human race finally figures out where it all came from.

Turning on protective systems in people should create centenarians who are vigorous and productive

Richard Miller forecasts the future

• 18 November 2006

In ageing research, the key breakthrough will be the elucidation of the molecular pathways that render cells from long-lived animals - whales, people, bats, porcupines - resistant to many forms of injury. Studies in worms have shown that mutations that extend lifespan do so by making them resistant not merely to one kind of stress (DNA damage, say, or oxidative injury) but to multiple forms of harm. Biologists are gradually showing that similar protective pathways also slow ageing in flies and mice, and that these cellular circuits date back further than the evolutionary branch point between yeast and us.

Figuring out how this "injury protection package" is turned on by evolution in long-lived animals, and by ultra-low-calorie diets and dwarfing mutations in mice, dogs, horses and probably people, will be the key step towards development of authentic anti-ageing pharmaceuticals that turn the same trick. It is now routine, in laboratory mammals, to extend lifespan by about 40 per cent. Turning on the same protective systems in people should, by 2056, be creating the first class of centenarians who are as vigorous and productive as today's run-of-the-mill sexagenarians.

Tissue Engineering will give limb regeneration

Ellen Heber-Katz forecasts the future

• 18 November 2006

I believe that the day is not far off when we will be able to prescribe drugs that cause severed spinal cords to heal, hearts to regenerate and lost limbs to regrow. People will come to expect that injured or diseased organs are meant to be repaired from within, in much the same way that we fix an appliance or automobile: by replacing the damaged part with a manufacturer-certified new part.

Advances in heart regeneration are around the corner, digits will be regrown within five to ten years, and limb regeneration will occur a few years later. Central nervous system repair will occur first with the retina and optic nerve and later with the spinal cord. Within 50 years whole-body replacement will be routine.

Billions of Universes?

Martin Rees forecasts the future

• 18 November 2006

I hope that in 50 years we will know the answer to this challenging question: are the laws of physics unique and was our big bang the only one? Theoretical horizons have recently expanded astonishingly. According to some speculations the number of distinct varieties of space - each the arena for a universe with its own laws - could exceed the total number of atoms in all the galaxies we see. Most space-times would be sterile or stillborn, but among this cornucopia there could still be immense numbers that allow big bangs that "fly" - allowing the emergence of the rich complexity that leads to atoms, stars, planets, biospheres and brains able to contemplate their origins. So do we live in the aftermath of one big bang among many, just as our solar system is merely one of many planetary systems in our galaxy?

Science will kill religion - not by reason challenging faith, but by offering a more practical moral framework for human interaction

Geoffrey Miller forecasts the future

* 18 November 2006

Applied evolutionary psychology should revolutionise life in three ways by 2056.

First, Darwinian critiques of runaway consumer capitalism should undermine the social and sexual appeal of conspicuous consumption. Absurdly wasteful display will become less popular once people comprehend its origins in sexual selection, and its pathetic unreliability as a signal of individual merit or virtue.

Second, studies of human happiness informed by evolution will reveal ever more clearly the importance of "social capital" - neighbourliness, close-knit communities, local family support, and integration between kids, adults and the elderly. This will, I hope, lead to revolutionary changes in urban planning, leading to a New Urbanist revival of mixed-use landscapes. Enlightened citizens will demand to live in village-type spaces rather than alienating suburbs of single-family isolation and unbearable commutes.

Third, evolutionary moral psychology will reveal the social conditions under which human moral virtues flourish. The US will follow the UK in realising that religion is not a prerequisite for ordinary human decency. Thus, science will kill religion - not by reason challenging faith, but by offering a more practical, universal and rewarding moral framework for human interaction. A naturalistic moral philosophy will replace the rotting fictions of theological ethics.

In these three ways, applied evolutionary psychology will help Enlightenment humanism fulfil its long-stalled potential to make us all brighter, wiser, happier and kinder.

Gravitational waves may be found: a relic of the universe 10-35 seconds after the big bang

• 18 November 2006, Rocky Kolb forecasts the future

The most significant breakthrough in cosmology will be the discovery of background gravitational waves that were produced in the very early universe, during the epoch of rapid expansion known as inflation.

We can already look out into space, and hence back in time, to 380,000 years after the bang using the cosmic microwave background radiation.

Similarly, by measuring the properties of the neutrino background we can look back to one second after the bang.

But gravitational waves are a relic of the universe 10^-35 seconds after the bang.

Nicholas Stern "globally spend 1% GDP on Carbon Dioxide limitation"

Chris Street edits in bold
Fred Pearce
15:02 30 October 2006

Nicholas Stern one of the world’s top economists today warned of a global recession that could cut between 5% and 20% from the world’s wealth later this century – unless the world invests now in the technologies needed to create a global low-carbon economy.

The cost of investment would be trivial by comparison with the possible damage, says Sir Nicholas Stern, former chief economist at the World Bank and an adviser to the British chancellor Gordon Brown, who commissioned the 600-page report.

Stern calls for a global investment of about 1% per year of global GDP over the next 50 years. He says that we should stabilise greenhouse gas concentrations at the equivalent of 500-550 parts per million of carbon dioxide, 25% above current levels. This is a level he regards as “high but acceptable”.

“Economically speaking, mitigation – taking strong action to reduce emissions – is a very good deal,” he says. “A 1% increase in prices is very marginal. We can continue to grow. But if we don’t [invest], the kind of changes that would happen will derail growth.”

Green benefit

Stern warns that climate change risks causing economic consequences “on a scale similar to those associated with the great wars and the economic depression of the first half of the 20^th century”. But in the long run we would all benefit from the cleaner, greener energy technologies.

His year-long investigation has not added to the scientific knowledge about the risks of climate change, he says, adding that evidence from international groups like the Intergovernmental Panel on Climate Change is “overwhelming”. But he has interpreted the implications of the scientists’ warnings for the world economy.

“There isn’t scientific certainty,” he says. “But the risks are very big.”

He forecasts huge disruption to African economies in particular as drought hits food production; up to a billion people losing water supplies as mountain glaciers disappear; hundreds of millions losing their homes and land to sea level rise; and potentially big increases in damage from hurricanes. The economic cost of failing to act could approach $4 trillion by the end of the century, he says.

Drastic cuts

Substantial climate change is now inevitable, Stern says. But the worst could be prevented if global emissions can be stabilised within 20 years and thereafter reduced by around 2% per year. “What we do in the next 10 or 20 years can have a profound effect on the climate in the second half of the century and in the next.”

Stern says the primary responsibility for action to cut greenhouse gas emissions lies with the rich industrialised world, which continues to produce most of the world’s emissions.

In response to the report, Gordon Brown has called for industrialised countries to cut their emissions by 30% by 2020 and at least 60% by 2050. Such drastic cuts are needed because CO₂, the main greenhouse gas responsible for climate change, accumulates in the atmosphere, lasting for hundreds of years before it is absorbed slowly by the oceans.

Chasm closed

Stern’s findings contradict some past claims by economists that the world would do better adapting to climate change than trying to halt it. Meanwhile, some scientists say the emissions cuts called for by Stern would not be enough to stave off dangerous climate change.

But Michael Grubb, a climate and energy analyst at of Imperial College London, UK, said: “The Stern Review finally closes a chasm that has existed for 15 years between the precautionary concerns of scientists and the cost-benefit views of many economists.”

London’s Mayor, Ken Livingstone, agreed: “For too long, necessary action to prevent catastrophic climate change has been delayed by fears that this would damage economic growth. Stern's report nails this myth – it is failure to take action on climate change that would be the real threat to future economic prosperity."

Livingstone continued: "I welcome Stern's call for an international carbon market and I look forward to working with him, Gordon Brown and indeed Al Gore on how London – a world centre for financial markets, energy companies and high tech industries – can play a leading role in this and the other measures he proposes.”

HeartScore

For the online interactive HeartScore - you can play Doctor and add your own details.

Intervention

Systolic blood pressure
is 130 mmHg, and that is above the normal range.

Raised blood pressure increases your risk for cardiovascular diseases.
It would be beneficial if your blood pressure was lowered from the present 130 mmHg to a level around xx mmHg.

You can contribute to this by choosing a diet rich on vegetables and fibres and by avoiding excessive intake of salt and animal fat.

If you increase your level of physical activity, it will also lead to a substantial reduction in your blood pressure.

In some cases, however, it is necessary to treat a high blood pressure with medicine.


Cholesterol

Your cholesterol is 5 mmol/L, and that is above the normal range.

The lower the cholesterol value gets, the lower the risk of cardiovascular disease.

I therefore recommend that your present cholesterol value of 5 mmol/L is lowered to a value around 5 mmol/L or less. This can be obtained by increasing the intake of vegetables and by eating less animal fat.

In severe cases, drugs may be needed to reduce a high cholesterol level.

GUIDELINES

Systolic Blood Pressure

Your patients blood pressure has been measured to 130 mmHg, 'and that is above the normal range.

The risk of cardiovascular diseases increases continuously as blood pressure rises from levels that are considered to be within the normal range.

The decision to start treatment, however, depends not only on the level of blood pressure, but also on an assessment of total cardiovascular risk and the presence or absence of target organ damage.

In patients with established CVD the choice of antihypertensive drugs depends on the underlying cardiovascular disease.

The decision to lower blood pressure with drugs depends not only on the total cardiovascular risk but also on presence of target organ damage.

Drug therapy should be initiated promptly in individuals with a sustained systolic blood pressure (SBP) > 180 mmHg and/or a diastolic blood pressure (DBP) > 110 mmHg regardless of their total cardiovascular risk assessment.

Individuals at high risk of developing CVD with sustained SBP of higher than 140 mmHg and/or DBP higher than 90 mmHg also require drug therapy.

For such individuals, drugs should be used to lower blood pressure to <140/90mmhg.>

• diuretics,
• betablockers,
• ACE inhibitors,
• calcium-channel blockers and
• angiotensin II antagonists.

In many clinical trials, blood pressure control has been achieved by the combination of two or even three drugs, and drug combination therapy is often also necessary in routine clinical practice.

In patients with several diseases requiring drug therapy, polypharmacy can become a major problem and good clinical management is required to resolve it.

In all patients, blood pressure reduction should be obtained gradually.
For most patients, the goal of therapy is blood pressure less than 140/90 mmHg, but for patients with diabetes and individuals at high total CVD risk, the blood pressure goal should be lower.

Cholesterol Guidelines
our patients cholesterol has been measured to 5 mmol/L, and that is above the normal range.

In general, total plasma cholesterol should be below 5 mmol/l (190 mg/dl), and LDL cholesterol should be below 3 mmol/l (115 mg/dl).

For patients with clinically established CVD and patients with diabetes the treatment goals should be lower:total cholesterol <4.5mmol/l(175mg/dl)>1.7mmol/l(150mg/dl),serve as markers of increased cardiovascular risk.

Values of HDL cholesterol and triglycerides should also be used to guide the choice of drug therapy.

Asymptomatic people at high multifactorial risk of developing cardiovascular disease, whose untreated values of total and LDL cholesterol are already close to 5 and 3 mmol/l, respectively, seem to benefit from further reduction of total cholesterol to <>8mmol/l (320mg/dl) and LDL-cholesterol>6mmol/l (240mg/dl) by definition places a patient at high total risk of CVD.

If the 10 year risk of cardiovascular death is >5%, or will become >5% if the individuals´ risk factor combination is projected to age 60, a full analysis of plasma lipoproteins should be performed, and intensive lifestyle advice, particularly dietary advice, should be given .

If values of total and LDL cholesterol fall below 5 mmol/l (190 mg/dl) and 3 mmol/l (115 mg/dl), respectively, and the total CVD risk estimate has become <>5%, lipid lowering drug therapy should be considered to lower total and LDL cholesterol even further.

The goals in such persistently high-risk individuals are to lower total cholesterol to < style="font-weight: bold;" size="4">Diet
General recommendations:

• foods should be varied, and energy intake must be adjusted to maintain ideal body weight
• the consumption of the following foods should be encouraged: fruits and vegetables, whole grain cereals and bread, low fat dairy products, fish and lean meat.
• oily fish and omega-3-fatty acids have particular protective properties
• total fat intake should account for no more than 30% of energy intake, and intake of saturated fats should not exceed a third of total fat intake. The intake of cholesterol should be less than 300 mg/day
• in an isocaloric diet, saturated fat can be replaced partly by complex carbohydrates, partly by monounsaturated and polyunsaturated fats from vegetables and marine animals
  Patients with arterial hypertension, diabetes, and hypercholesterolemia or other dyslipidemias should receive specialist dietary advice.

Priorities
The priorities for CVD prevention in clinical practice are :

• Patients with established coronary heart disease, peripheral artery disease and cerebrovascular atherosclerotic disease
• Asymptomatic individuals who are at high risk of developing atherosclerotic cardiovascular disease because of
• multiple risk factors resulting in a 10 year risk of 5% now (or if extrapolated to age 60) for developing a fatal CVD event
• markedly raised levels of single risk factors: cholesterol 8 mmol/l (320 mg/dl), LDLcholesterol 6 mmol/l (240 mg/dl), blood pressure 180/110 mmHg
• diabetes type 2 and diabetes type 1 with microalbuminuria
• Close relatives of
• patients with early onset atherosclerotic cardiovascular disease
• symptomatic individuals at particularly high risk
• Other individuals encountered in your clinical practice

Strategies
Strategies to make behavioural counselling more effective include:

• develop a therapeutic alliance with the patient
• gain commitments from the patient to achieve lifestyle change
• ensure the patient understands the relationship between lifestyle and disease
• help the patient overcome barriers to lifestyle change
• involve the patient in identifying the risk factor(s) to change
• design a lifestyle modification plan
• use strategies to reinforce the patients´ own capacity to change
• monitor progress of lifestyle change through followup contacts
• involve other health care staff wherever possible

SCORE
This new model for total risk estimation based on the SCORE (Systematic Coronary Risk Evaluation) system is now recommended and has several advantages.

The SCORE risk assessment is derived from a large dataset of prospective European studies and predicts fatal atherosclerotic CVD events over a ten year period.

This risk estimation is based on the following risk factors: gender, age, smoking, systolic blood pressure and total cholesterol.

The threshold for high risk based on fatal cardiovascular events is defined as "higher than 5%" , instead of the previous "higher than 20%" using a composite coronary endpoint.

This SCORE model has been calibrated according to each European country´s mortality statistics. In other words, if used on the entire population aged 40-65, it will predict the exact number of fatal CVD-events that eventually will occur after 10 years.

Using HeartScore total CVD risk can also be projected to age 60 which may be of particular importance for guiding young adults, at the age of 20 or 30, at low absolute risk, but already with an unhealthy risk profile, which will put them at much higher risk when they grow older.

Relative risk can also be estimated from the pie charts.

You can read more about the SCORE project in European Heart Journal, 2003, 24; 987-1003.

Peer Review

Peer review (wikipedia) (known as refereeing in some academic fields) is a process of subjecting an author's scholarly work or ideas to the scrutiny of others who are experts in the field. It is used primarily by editors to select and to screen submitted manuscripts, and by funding agencies, to decide the awarding of monies for research.The peer review process is aimed at getting authors to meet the standards of their discipline and of science generally. Publications and awards that have not undergone peer review are likely to be regarded with suspicion by scholars and professionals in many fields. Even refereed journals, however, have been shown to contain error, fraud and other flaws that undermine their formality.

The Root of all Evil? tv documentary by Richard Dawkins

The Root of All Evil? (wikipedia) is a television documentary, written and presented by Richard Dawkins, in which he argues that the world would be better off without religion. The documentary was first broadcast in January 2006, in the form of two 45 minute episodes (excluding advertisement breaks), on Channel 4 in the UK. Dawkins has said that the title "The Root of All Evil?" was not his preferred choice, but that Channel 4 had insisted on it to create controversy.^[1] His sole concession from the producers on the title was the addition of the question mark. Dawkins has stated that the notion of anything being the root of all evil is ridiculous.^[2] Dawkins' book The God Delusion, released in September 2006, goes on to examine the topics raised in the documentary in greater detail.

BMI - Body Mass Index

I'm overweight. BMI and Waist to hip ratio both indicate that fact.

At 5'7.5" and 12st 131bs or 181 pounds (was 13st 8lbs a few months ago!) my BMI is 27.9.

BMI is Body Mass Index defined by dividing weight in kilogrammes by my height in metres squared. BMI = kg/m2.

My current weight loss goal is to stabilise at 155 pounds (11st 1lb) giving a BMI of 23.9.

For a BMI of 24.9 my weight would be 161.5 pounds (11st 7.5lbs).

For a BMI of 20.9 my weight would be 135 pounds (9st 9Ibs).

I use a simple BMI calculator.

Back in February 1987 I was 11st 13lbs (BMI 25.8 - overweight) and by July 1987 in my first diet (strict calorie counting + exercise) I lost 2 stone to 9st 13lbs (BMI 21.4 - normal weight). Sharon said I looked emaciated at this weight!

By August 1990, 3 years on, I had put on all the weight I had lost in 1987 diet.

Sharon's weight today is 10st 2Ibs, 5'1" - BMI is 26.6. A 24.9 BMI for her is 9st 6Ibs. A 23.9 BMI would be 9st.

But how were these figures calculated in the first place? And is their any variation of these classifications? Wikipedia BMI page has answers.

the following are common definitions of BMI categories:

• Starvation: less than 15
• Underweight: less than 18.5
• Ideal: from 18.5 to 25
• Overweight: from 25 to 30
• Obese: from 30 to 40
• Morbidly Obese: greater than 40

During the past 20 years, says CDC obesity among adults has risen significantly in the United States. The latest data from the National Center for Health Statistics show that 30 percent of U.S. adults 20 years of age and older—over 60 million people—are obese. The U.S. National Health and Nutrition Examination Survey of 1994 indicates that 59% of American men and 49% of women have BMIs over 25.

Being overweight increases the risk of many diseases and health conditions, including the following:

• Hypertension
• Dyslipidemia (for example, high total cholesterol or high levels of triglycerides)
• Type 2 diabetes
• Coronary heart disease
• Stroke
• Gallbladder disease
• Osteoarthritis
• Sleep apnea and respiratory problems
• Some cancers (endometrial, breast, and colon)

BMI or Quetelet Index was invented between 1830 and 1850 by the Belgian polymath, Adolphe Quetelet during the course of developing "social physics".

The BMI has become controversial because many people, including physicians, have come to rely on it for medical diagnosis - but that has never been the BMI's purpose. It is meant to be used as a simple means of classifying sedentary (physically inactive) individuals with an average body composition.

I wouldn't say i was physically inactive (how is that defined?) - I walk Jazzie the dog most days for an hour or so and ride a bike occassionally on a CRABS ride.

Have i got an average body composition?

BMI accuracy in relation to actual levels of body fat is easily distorted by such factors as fitness level, muscle mass, bone structure, gender, and ethnicity. As a general rule, developed muscle contributes more to weight than fat and the BMI does not account for this. Therefore a person with more muscle mass, such as a body-builder, will seem to be overweight. People who are mesomorphic tend to have higher BMI numbers than people who are endomorphic, because they have greater bone mass and greater muscle mass, respectively, than do endomorphic individuals.

Similarly, an ectomorphic individual could conceivably receive an unhealthily low reading, when in fact their body type makes them naturally thin no matter what they eat.

International BMI variations

These recommended distinctions along the liner scale may vary from time to time and country to country. In 1998, the U.S. National Institutes of Health brought U.S. definitions into line with World Health Organization guidelines, lowering the normal/overweight cut-off from BMI 27.8 to BMI 25. This had the effect of redefining 30 million Americans, previously "technically healthy" to "technically overweight". It also recommends lowering the normal/overweight threshold for South East Asian body types to around BMI 23, and expects further revisions to emerge from clinical studies of different body types.

Waist-to-Hip Ratio vs BMI May Be More Accurate Predictor of CV Risk

Chris Street edits in bold.

Wikipedia article Waist to Hip Ratio was updated by Chris Street today:-

WHR not Body mass index (BMI), is the best obesity measure for assessing a person’s risk of heart attack. If obesity is redefined using WHR instead of BMI, the proportion of people at risk of heart attack worldwide increases threefold.^[2][3]

News Author: Laurie Barclay, MD
CME Author: Charles Vega, MD, FAAFP

Release Date: November 7, 2005;

Nov. 7, 2005 — Changing the standard from body mass index (BMI) to waist-to-hip ratio would improve accuracy of cardiovascular (CV) risk assessment across ethnic groups, according to the results of a standardized case-controlled study reported in the Nov. 5 2005 issue of The Lancet. The editorialists suggest that this marker should replace BMI.

Obesity and the risk of myocardial infarction in 27 000 participants from 52 countries: a case-control study
Waist-to-hip ratio, not body mass index (BMI), is the best obesity measure for assessing a person’s risk of heart attack, conclude authors of a study published this week. If obesity is redefined using waist-to-hip ratio instead of BMI, the proportion of people at risk of heart attack increases threefold. Heart-attack patients had a strikingly higher waist-to-hip ratio than people in a control group, irrespective of other cardiovascular risk factors......

"Our findings suggest that substantial reassessment is needed of the importance of obesity for cardiovascular disease in most regions of the world," lead author Salim Yusuf, MBBS, PhD, from Hamilton General Hospital-McMaster Clinic in Ontario, Canada, said in a news release.

The INTERHEART Study was a standardized case-control study of acute myocardial infarction (MI), which included 27,098 participants (12,461 cases and 14,637 controls) of varying ethnicity from 52 countries. The investigators evaluated the relationship between BMI, waist and hip circumferences, and waist-to-hip ratio to MI overall and in each ethnic group.

"Waist-to-hip ratio shows a graded and highly significant association with myocardial infarction risk worldwide," the authors write. "Redefinition of obesity based on waist-to-hip ratio instead of BMI increases the estimate of myocardial infarction attributable to obesity in most ethnic groups."

Study limitations include possible underestimation of the true contribution of visceral fat to CV disease risk, case-control design, and inability to determine the relationship between the different measures of obesity on other outcomes or whether there is an increased risk for some diseases in those who are lean.

"The INTERHEART investigators place what seems to be the final nail in the casket for body-mass index as an independent cardiovascular risk factor," Drs. Kragelund and Omland write. "The main message from the new INTERHEART report is that current practice with body-mass index as the measure of obesity is obsolete, and results in considerable underestimation of the grave consequences of the overweight epidemic. A direct consequence of these findings is that, for assessment of risk associated with obesity, the waist-to-hip ratio, and not body-mass index, is the preferred simple measure."

Lancet. 2005;366:1589-1591, 1640-1649

Clinical Context

Risk factors for MI have been extensively studied, but most of this research has focused on individuals in Europe and North America. The INTERHEART study reached out beyond cultures and ethnicities traditionally involved in medical research to include patients in Asia, Africa, the Middle East, and South America. In the original report from this study, published in the Sept. 11 - 17, 2004, issue of The Lancet, the authors found that common risk factors for MI included smoking, raised ApoB/ApoA1 ratio, history of hypertension, diabetes, abdominal obesity, and psychosocial factors. However, the intake of fruits and vegetables as well as alcohol consumption was protective against MI.

These data from the INTERHEART study suggested that waist circumference might be a better predictor of CV risk than another well-known anthropometric measurement, the BMI. The current analysis focuses on this issue.

Study Highlights

• The study was a case-control trial comparing patients with their first MI vs age- and sex-matched controls. Patients with MI were eligible for study participation if they did not have cardiogenic shock or any major chronic illness. Subjects were evaluated in centers in 52 countries and 6 continents.
• Cases and controls were compared in terms of demographic factors, socioeconomic status, lifestyle, medical risk factors, and a personal and family history of CV disease.
• 12,461 cases were compared with 14,637 controls. Logistic regression was used to account for other confounding CV risk factors in comparing anthropometric values.
• For the overall cohort, the mean BMI was lowest in Asia, intermediate in Europe, South America, and Africa, and highest in North America, the Middle East, and Australia. However, waist-to-hip ratio exhibited different geographic trends, being lowest in China, intermediate in North America, Europe, and other parts of Asia, and highest in the Middle East and South America.
• Subjects in the highest quintile of BMI had an OR of MI of 1.44 vs those in the lowest quintile. However, the risk for MI associated with BMI was obviated after adjustment for other risk factors.
• Conversely, subjects in the highest quintile of waist-to-hip ratio had an OR of MI of 1.77 vs those in the lowest quintile. After adjustment for other risk factors, this OR decreased to 1.33, but it remained statistically significant.
• The risk of MI increased progressively with values for waist-to-hip ratio, with no evidence of a threshold. The association between MI and waist-to-hip ratio was significant regardless of BMI, sex, age, or the presence of other CV risk factors.
• The waist-to-hip ratio, waist-to-height ratio, waist circumference, and hip circumference were all better predictors of MI vs BMI. BMI was the worst predictor of MI across all 8 ethnic groups, whereas waist-to-hip ratio was the best predictor in 6 of the 8 groups.

Waist to Hip ratio

I'm overweight. BMI and Waist to hip ratio both indicate that fact.

At 5'7.5" and 12st 11 1bs or 179 pounds at 30th December 2006 (was 13st 8lbs a few months ago!) my BMI is 27.6.

Methods for actually measuring body fat percentage are preferable to BMI for measuring healthy body size. Mayo Clinic researchers say the BMI doesn't accurately predict risk of cardiovascular death because it doesn't distinguish between muscle and fat. They say a better measure may be your Waist-hip ratio (wikipedia). The evidences is that in an analysis at Mayo Clinic led by Lopez-Jiminez of 40 studies involving 250,000 people, heart patients with normal BMIs were at higher risk of death from cardiovascular disease than people whose BMIs put them in the "obese" range. The ones in the study who had the highest death rates were people who weighed the least; in other words, they had the lowest BMIs (reference citation required).

My Waist-hip ratio is 104cm/99cm (41"/39") or 1.05, Sharon's is 34"/41" (86cm/104") or 0.83.

According to NICE NHS booklet (December 2006): target for men is <94cm>

Source: NICE Guideline Booklet

Women within the 0.7 range have optimal levels of estrogen and are less susceptible to major diseases such as diabetes, cardiovascular disorders and ovarian cancers. Men with WHRs around 0.9, are more healthy and fertile with less prostate and testicular cancer.

WHR is considered to be factor in a person's attractiveness. Women with a 0.7 WHR are often rated as more attractive by men regardless of culture, race, religion or ethnicity. Such diverse beauty icons as Marilyn Monroe, Twiggy, Sophia Loren, Kate Moss, Salma Hayek and even the Venus de Milo all have ratios around 0.7, even though they have significantly different weights. Congruent with an evolutionary perspective, evidence suggests that humans use subtle biological cues, such as WHR, to indicate mate potential and fertility.

Abdominal Obesity in INTERHEART study

This study found that BMI showed a modest and graded association with risk of Myocardial Infarction MI (Heart Attack). Waist and hip circumferences were both highly significantly associated with risk of MI. Waist-to-hip ratio was a better measure of risk than waist circumference alone.

Obesity and CVD: Biologic Mechanisms

The biologic mechanisms underlying the relation between obesity and cardiovascular risk are unclear. The waist-to-hip ratio is a simple measure for visceral obesity, and visceral adiposity is a manifestation of the metabolic abnormalities that underlie risk of future CVD events. It may be that the ratio of fat to muscle (sarcopenic adiposity) can be a measure of risk of CVD, which is best estimated by waist-to-hip ratio.

Visceral adiposity is the fat that is integrated within the abdominal organs, as opposed to subcutaneous fat, as measured by the "skin-fold" test.

These results suggest that it is not how much fat a patient has, but where it is stored that contributes to overall cardiovascular risk, insulin resistance, and glucose tolerance. It means that waist and hip circumferences provides a predictive power greater than that provided by BMI for estimating the risk of MI.

With the redefinition of abdominal obesity based on waist-to-hip ratio instead of BMI, the estimated risk of MI attributable to obesity was higher than previously assumed and the risk of MI rose progressively with increasing values for waist-to-hip ratios with no evidence of a threshold.

The global burden of obesity has been substantially underestimated by the reliance on BMI.

• INTERHEART estimated
  
• 63% of heart attacks were due to abdominal obesity indicated by a high waist to hip ratio (for men >0.95, for women >0.85).
  
• Those with abdominal obesity were at over twice the risk of a heart attack compared to those without.
  
• Abdominal obesity was a much more significant risk factor for heart attack than BMI.
• men (33%) and women (30%) had a high waist to hip ratio.
• benefits may accrue by redistribution of the body's fat stores to the hips or by increasing muscle mass.